This invention relates an improved method of dry quenching red hot coke in a dry quenching apparatus, and more particularly to a method of controlling the pressure of gas circulating within the quenching apparatus to prevent escape of the gas from a top charging port of a quenching station, combustion of coke by absorbing the air, or damages to the facilities caused by abnormal pressure, and to thereby carry out a safe and stable dry quenching operation.
Recently, there has been developed a dry quenching method for red hot coke from a coke oven, which is performed by an apparatus provided with a charging port at the top thereof for the red hot coke, and an exit port at its bottom. Closed gas-circulating ducts communicate with a quencher having a vertical cooling chamber therein, and a heat-exchanger, and a blower are provided whereby the quenching gas passes upwardly through the body of coke filled in the cooling chamber.
In this kind of the conventional operation, N.sub.2 gas is supplied into the circuit to maintain the composition of the quenching gas constant, or air enters the system, resulting in changes in the amount or pressure of the flowing gas. In view of such circumstances, the prior art has built a countermeasure which arranges a damper and a bleeder to control the amount of the gas to the cooling chamber by the damper and to discharge surplus gas through the bleeder, the damper being arranged at a gas introducing portion positioned at the lower part of the cooling chamber and the bleeder being arranged at the exit of the fan.
However, this method of controlling the amount of gas flowing by controlling the damper cannot keep constant a diverging point between a positive pressure and a negative pressure in the circulating system (hereinafter briefly called a diverging point), that is, the zero point moves, upon closing the damper, from the gas leading portion at the top of the cooling chamber to a point in the direction of the heat exchanger, or it positions below the gas leading portion upon opening the damper. Consequently, when the damper is closed, the pressure at the upper portion of the cooling chamber becomes positive, and it becomes negative when opened, with the result that when the cover is opened for charging the coke, the gas bearing dust, CO and other elements is exhausted in large quantities and pollutes the environment, or conversely a large quantity of air is absorbed during the charging of the coke due to the negative pressure within the top portion of the quenching station and this causes a combustion loss in the coke. Further although discharging of the surplus gas may control overpressure caused by the air introduced through the duct between the quencher and the heat exchanger, the desired controlling cannot be provided for on the overpressure within the cooling chamber which is caused by N.sub.2 gas introduced at the quenching gas introducing part, and for the changes of the pressure within the circulating system which are caused by the overpressure at the top of the cooling chamber created by gas generated from the red hot coke, and therefore the load is unnecessarily increased on the heat exchanger, fan, ducts or other facilities.
Thus, there still remains problems to be solved in the prior art.